Chronic neuropathic pain develops when nerves are damaged, often leading to persistent and difficult-to-treat symptoms. Standard medications provide meaningful relief for only a small portion of patients, which has fueled interest in alternative options such as cannabis-based medicines. These products range from herbal cannabis to specific compounds derived from the plant, including tetrahydrocannabinol (THC), and are used in forms such as inhaled products, mouth sprays, tablets, creams, and skin patches.

How the Evidence Was Evaluated

To assess how well these treatments work, researchers analyzed 21 clinical trials involving more than 2,100 adults. In these studies, cannabis-based medicines were compared with placebo treatments over periods lasting from two to 26 weeks.

The products studied fell into three main categories. Some contained mostly THC, the psychoactive component of cannabis. Others were primarily made up of cannabidiol (CBD), a compound that does not cause intoxication. A third group included balanced products with similar amounts of THC and CBD.

Results Show No Meaningful Benefit Over Placebo

Across all three categories, the review found no high-quality evidence that cannabis-based medicines reduced neuropathic pain more effectively than placebo. Although a few participants using products that combined THC and CBD reported slight improvements, these changes were too small to be considered clinically meaningful.

Information on adverse effects was not reported consistently across the trials, making it difficult to draw firm conclusions about safety. Overall confidence in the data on side effects ranged from low to very low. Products containing THC were linked to increased reports of dizziness and drowsiness, and there may have been a higher number of participants who stopped treatment because of these side effects.

Researchers Call for Better Studies

“We need larger, well-designed studies with a treatment duration of at least 12 weeks that include people with comorbid physical illnesses and mental health conditions to fully understand the benefits and harms of cannabis-based medicines,” said Winfried Häuser, clinician and lead author, from Technische Universität München and Medical Center Pain Medicine and Mental Health Saarbrücken. “At present, the quality of most of the trials is too poor to draw firm conclusions.”

The authors conclude that the current evidence remains weak and uncertain, highlighting the need for higher-quality research before cannabis-based medicines can be recommended for people living with chronic neuropathic pain.